Typically, weather data, such as temperature or atmospheric pressure, is measured from a physical weather station or other physical weather value measuring device at a particular location. This weather data provided is generally collected, stored and made available to a user. The user upon collecting or receiving the weather data can further analyze, or make additional calculations using this weather data. For example, a user might take one or more weather values, such as temperature and calculate Evapotranspiration (ET), or amount of water used by a plant for those measured weather conditions. The user may then manually enter or communicate this value to an irrigation controller which in turn calculates the appropriate amount of irrigation based on the ET and the user input information.
FIG. 1 shows a prior art irrigation system in which a local weather station 112 located within an irrigation area 130 provides weather information that can be used to control an irrigation system 140 within the irrigation (site) area 130. The weather information can be stored in non-local storage 114, but still represents the weather at the site of the irrigation system. The irrigation system can also receive weather values from a non-local data source 116 (such as a satellite), but the data (weather information) of the non-local data source 116 reflects weather of the site (irrigation) area 130. A processor 150 receives the irrigation area weather information and controls the irrigation system 140.
Irrigation systems that include the above-described controller to control the amount of irrigation based on calculated ET can be sub-optimal because the physical weather measuring parameter device may be located somewhere other than where the irrigation area is located. Therefore, the calculated ET may not provide an accurate estimate of the irrigation required because the ET is calculated based on physical weather measurements that do not accurately represent the weather at the irrigation area.
It is desirable to control a resource demand system, wherein weather value calculated for the resource demand system can be validated, adjusted and/or trends identified.